The dataset provides rare high quality meteorological observations from sea-ice regions of the Arctic Ocean. They enable analysis of meteorological conditions and provide context for other measurements and analysis associated with the expedition.

The measurements are from the CL51 ceilometer operating on Icebreaker Oden’s 7th deck at 25 m above sea level during the Arctic Ocean 2016 (AO2016) expedition to the central Arctic Ocean in August and September 2016.

Data description

Data from the FMI Vaisala CL51 ceilometer, averaged over either 1 or 30-minute intervals. Two data formats are available: Matlab (.mat) and NetCDF (.nc), with an accompanying readme (.rtf) file.

Comments

The height to the lowest cloud base, and up to two additional cloud bases when the lowest cloud layer does not cover the whole sky, was measured by a Vaisala CL51 ceilometer, located above Oden’s bridge on the 7th deck. The ceilometer, owned by the Finnish Meteorological Institute (FMI), was deployed as part of the Stockholm University weather station.

The system uses a proprietary Sky Condition algorithm to determine cloud fraction at up to five levels, converting single-point time-series measurements to time-averaged area coverage. The system additionally recorded the backscatter profile, and hence serves as a so-called poor-man’s LiDAR. When the attenuation of the laser beam reaches a threshold, like in a dense fog, it switches to reporting vertical visibility, rather than cloud-base height.

Data from the ceilometer are combined into a cruise-length file. The data are time-averaged to both 1-minute and 30-minute intervals, to correspond with the micrometeorological averaging periods used for the mast sensors.

Version history

Version 2.0

Essentially the same data as in version 1.0, but with an updated readme file and new metadata within the nc files.

Version 1.0

Initial release.

Contact information

Email address

[javascript protected email address]

Phone number

+46 8 16 4373

Postal address

John Prytherch
Department of Meteorology (MISU)Stockholm University
SE-106 91 StockholmSweden

Metadata

GCMD science keywords

Earth science > Atmosphere

GCMD location

Ocean > Arctic Ocean

Status

Completed

Dataset language

English

Project

Arctic Ocean 2016 expedition. These data were processed as part of the Arctic Climate Across Scales (ACAS) project, funded by the Knut and Alice Wallenberg Foundation. Project PI Michael Tjernström (MISU).